The invention relates to attachable couplings of the male-stem, ferrule type for use with reinforced, flexible hose but more particularly, the invention relates to a ferrule with an insert for gripping a hose end.
Couplings of the type that are post assembled to an end of a finished hose product typically have a male-stem portion that is insertable into a hose end and a ferrule that is concentric with the male-stem. Together, the male-stem and ferrule define an annular cavity for receiving a hose end. A coupling is retained by pinching the hose end in the annular cavity between the ferrule and stem such as by either radially reducing some part or element of the ferrule or by radially increasing the size of the male-stem.
Some couplings are of the reusable type and use a mechanical means of the coupling such as threaded members that activate means for pinching a hose against a stem. An example of such a reusable coupling appears in European patent 0 241 651 where a plurality of coaxial rings having alternating frustoconical surfaces are axially pressed together by a threaded member to wedge alternate rings radially inwardly. The so wedged rings pinch a hose against a stem. Such reusable couplings are usually expensive because the co-acting parts forming the coupling are typically machined from barstock. Furthermore, the amount of pinching cannot be precisely controlled for a range of hoses when the coupling is attached to a hose.
Crushable types of ferrules that may be of different sizes for different hose constructions having the same bore size are preferred for accurately controlling how an end of a hose is pinched. The present invention is directed to radially reducing the size of the ferrule by crushing it to a smaller diameter as by crimping using a plurality of circumjacently arranged die fingers.
Oftentimes, a serrated stem with a ferrule locking collar is used for high pressure hoses that are subjected to pressure impulses. For convenience of assembly, a ferrule may be pre-attached to a stem such as by crimping an end portion of the ferrule to the ferrule locking collar. While preattachment of a ferrule to a stem has advantages associated with reducing the number of parts for assembly to a hose, it introduces a disadvantage as to the number of parts required for a line of hose sizes because some hoses require the same size stem but different size ferrules. For example, three different size ferrules may be used with the same size stem for coupling .5 in. ID hose having different tube, reinforcement, and cover combinations. Consequently, some manufacturers prefer to select an appropriate ferrule for a hose when it is to be crimped on a hose so as to minimize inventory.